Negatively or positively charged microspheres were obtained by addition of methacrylic acid (MAA) or dimethylaminoethyl methacrylate(DMAEMA) to the polymerization mixture.

• 将甲基丙烯酸(MAA)和甲基丙烯酸二甲氨乙酯(DMAEMA)加入以上聚合物中使微球具有正负电性。